#ifndef _CONTEXT_H_
#define _CONTEXT_H_

class State;

class Context {
public:
  Context();
  Context(State* state);
  ~Context();
  void OprationInterface();
  void OperationChangState();
protected:

private:
  friend class State; //表明在 State 类中可以访问 Context 类的 private 字段

  bool ChangeState(State* state);

private:
  State* _state;
};

#endif //~_CONTEXT_H_
